There is a window stuck on my desktop that won't go away.

As I said in the title, a window is stuck on my Mac screen and I can't remove it. I can't click on it, and when I hover over the red, yellow, and green buttons, they don't show the little (x) or the (-) and they also don't show the fullscreen icon. The window might as well be part of my wallpaper since I can't interact with it or hover over it. Can someone with a similar experience help me with this situation?